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ERIC Number: EJ1109313
Record Type: Journal
Publication Date: 2014-Dec
Pages: 20
Abstractor: As Provided
ISSN: EISSN-2330-8516
What Differential Weighting of Subsets of Items Does and Does Not Accomplish: Geometric Explanation. Research Report. ETS RR-14-20
Carlson, James E.
ETS Research Report Series, Dec 2014
A little-known theorem, a generalization of Pythagoras's theorem, due to Pappus, is used to present a geometric explanation of various definitions of the contribution of component tests to their composite. I show that an unambiguous definition of the unique contribution of a component to the composite score variance is present if and only if the component scores are uncorrelated. I further show the effect of differentially weighting the composites on the definitions of unique contributions and discuss some of the implications for composite score reliability and validity.
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Publication Type: Journal Articles; Reports - Research
Education Level: N/A
Audience: N/A
Language: English
Sponsor: N/A
Authoring Institution: N/A
Grant or Contract Numbers: N/A